Conventionally, for the purpose of supporting vehicle driving, a technique has been known for detecting objects that exist outside of a vehicle, or for monitoring a relative positional relationship between such objects and a driver's own vehicle. In particular, various methods have been proposed to capture images using a camera (image capturing unit) that is mounted on the front of a vehicle, and to detect objects based on the captured images obtained therefrom.
For example, in “Nighttime Pedestrian Detection”, ViEW 2008, Proceedings of the Vision Engineering Workshop, pages 224-228, a technique is disclosed in which, after a number of area candidates have been extracted by performing a simple primary identification process, e.g., boosting, having a short computation time with respect to an entire captured image, a detailed secondary identification process, e.g., SVM (Support Vector Machine), having a long computation time is applied sequentially with respect to each of the area candidates.